Development of a small scale instrumented tracked vehicle for mobility studies and prediction

Small scale tracked robot vehicles are widely used for a number of applications ranging from industrial applications, such as mining and agricultural, to hazardous and complex applications in defense, toxic cleanup, space exploration, etc. These tracked robotic vehicles are often chosen to accomplish a set of objectives in unstructured, dynamic, and uncertain environments. To design a tracked robotic vehicle to meet a particular objective, there are number of fundamental factors that are critical for mobility such as drive motor torque, thrust force, resistive forces, etc. The goal of this thesis was to investigate the difficulty in evaluating critical mobility characteristics for small scale tracked vehicles, particularly at the 20:1 scale. The study was further constrained by examining low cost solutions. A tracked robotic vehicle based on commercial-off-the-shelf (COTS) hardware was selected, and a complete sensing, instrumentation, and control system was developed for baseline studies. To quantify data and validate the system, we calibrated independent subsystems, which included microcontrollers, motion sensors, and torque measurement using a motor sensing resistor. We critically analyzed the data through various relationships (e.g., vehicle velocity vs slip, thrust force vs vehicle weight, traction coefficient vs slip etc) that exist among common performance characteristics used for full-scale tracked vehicles. Based on the data obtained, we predicted and proved practically the tracked vehicle performance, including maximum grade that can be negotiated. At the end of this research, we found that if some critical factors like sensor and effectors noise is controlled properly, the data can be interpreted effectively and successfully to assess the performance of tracked vehicle on hard surfaces. Additional considerations would have to be made to investigate effectiveness on deformable terrains, as the present work was confined to hard surfaces for establishing the viability of the approach